Background: The increasing prevalence of obesity worldwide is associated with a massive increase in the number of yearly performed bariatric procedures, many of them purely restrictive. Consequently, a growing number of surgical revisions are necessary, and conversion to Roux-en-Y gastric bypass (RYGBP) is a common option. So far, few series including mostly patients reoperated using open surgery,and limited follow-up, have been reported.Patients and methods: Retrospective analysis of prospectively collected data of all patients undergoing revisional RYGBP in our two departments.Results: Between June 1999 and February 2011, 186 patients were submitted to revisional RYGBP, 161 women and 25 men with a mean age of 43 years. Their mean initial BMI was 45,3 kg/m2, their mean nadir BMI between the index operation and revision was 34, and their mean pre-revision BMI was 38,5. The initial procedure was gastric banding in 134 (72 %) patients, VBG in 48 (25,8 %), RYGBP in 5 (2,7 %), and others in 3. The main indications for revision were complications from the primary procedure with or without weight regain. A laparoscopic approach was usedin 137 (73,7 %) cases. Overall early morbidity was 18,8 %, and major morbidity was 3,2 %. Comparing patients in the first, second and last third of our experience, the percentage of patients operated using a laparoscopic approach increased from 53,2 % to 71 % and finally 96,7 %, and overall morbidity decreased from 27,4 % to 24,2 % and then 4,8 %. There were more wound infections after laparotomy (22,4 versus 2,9 %, p<0,001). There was no mortality. The mean BMI remained between 30 and 32 up to nine years after revision. Up to this limit, a BMI of <35 was maintained in between 75 and 83 % of the patients.Conclusions: Revisional RYGBP proves to be an effective and safe procedure. It can be performed by laparoscopy in most cases, especially as experience increases., It is associated with an acceptable morbidity, though higher than with primary RYGBP. Long-term results are equivalent to those of primary RYGBP, and can be considered as very satisfactory considering the fact that, on average, patients requiring redo surgery represent a sub-selection of difficult bariatric patients.